The present invention relates to a system suitable for exploiting oil/gas fields and, more particularly, subsea fields and a method of installing such a system.
Conventional oil/gas fields have a plurality of wells linked to a host facility which receives the oil/gas via flow lines. A conventional underwater oil/gas field may include modularised processing systems between the wells and the host facility.
GB 2261271 describes a modularised processing system which is used to separate a mixture of oil, gas and water from wells into its individual components. The system comprises an offshore installation in which interchangeable modules are individually supported in a support framework located on the seabed, the modules being used to separate the mixture. Two-part connectors enable modules to be lowered from the surface of the sea into the framework and be connected up to the wells. The modules can also be retrieved from the system so that maintenance can be carried out on them when they are out of the water.
Such a framework is a large, heavy structure which requires expensive guidance means for guiding the modules into the framework.
It is therefore an object of the present invention to provide an improved system for such modules and a method of installation of such a system.
According to one aspect of the present invention there is provided a method of installing a system, comprising the steps of:
installing a foundation into ground;
fixing a docking unit to the foundation via a single connection;
connecting flowlines to the docking unit; and connecting at least one retrievable substantially autonomous module to the docking unit so that the or each module is able to act on fluid received from the flowlines.
By having a single connection between the docking unit and the foundation, the installation of the docking unit is made far simpler. The single connection may comprise a connection of a type used for a well head.
The step of fixing the docking unit to the foundation via a single connection may comprise clamping a mating clamp arrangement attached to one of the docking unit or the foundation to a protrusion attached to the other of the docking unit or foundation. The protrusion is preferably substantially centrally placed on the docking unit or foundation.
The step of connecting at least one retrievable substantially autonomous module to the docking unit desirably includes actuating isolation means to connect at least one module to the flowlines, the isolation means comprising a first portion in the module and a complementary second portion in the docking unit.
The method may include an uninstalling step of disconnecting one said retrievable substantially autonomous module from the docking unit, without affecting the operation of any other retrievable substantially autonomous module with the flowlines and without effecting the connection of any other such module. The uninstalling step desirably includes actuating the isolation means to isolate the module being disconnected from the docking unit and the flowlines connected thereto.
The isolation means may comprise an isolation connector of a type used for a well head. The isolation means may comprise a multi-ported valve isolation connector.
It may be desirable for the method to include the steps of connecting a first portion of a power connector to the docking unit, the first portion of the power connector being connected to a power source remote from the docking unit, and connecting a complementary second portion of the power connector in one said retrievable substantially autonomous module to the first portion so that the power source is able to provide power to the module. The power connector may be adapted to carry control signals to or from the module.
The step of connecting at least one retrievable substantially autonomous module to the docking unit may include providing guiding means to guide said module into connection with the docking unit. The guiding means desirably ensures that the second portion of the power connector of the module engages the first portion of the power connector on the docking unit.
The ground is preferably a seabed. The foundation may comprise a single pile.
According to another aspect of the present invention there is provided a system comprising:
a foundation installed into ground;
a docking unit fixed to the foundation via a single connection; and
at least one retrievable substantially autonomous module, the or each module being connected to the docking unit so that the or each module is able to act on fluid received from the flowlines.
The system has a much smaller xe2x80x9cfootprintxe2x80x9d on, say, a seabed, and is also lighter and cheaper than a system having a support framework for interchangeable modules.